/*
 * Copyright (C) 2008 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.emay.sdk.util.json.gson;

import java.util.Map;
import java.util.Set;

import cn.emay.sdk.util.json.gson.internal.LinkedTreeMap;

/**
 * A class representing an object type in Json. An object consists of name-value
 * pairs where names are strings, and values are any other type of
 * {@link JsonElement}. This allows for a creating a tree of JsonElements. The
 * member elements of this object are maintained in order they were added.
 *
 * @author Inderjeet Singh
 * @author Joel Leitch
 */
public final class JsonObject extends JsonElement {
	private final LinkedTreeMap<String, JsonElement> members = new LinkedTreeMap<String, JsonElement>();

	@Override
	JsonObject deepCopy() {
		JsonObject result = new JsonObject();
		for (Map.Entry<String, JsonElement> entry : members.entrySet()) {
			result.add(entry.getKey(), entry.getValue().deepCopy());
		}
		return result;
	}

	/**
	 * Adds a member, which is a name-value pair, to self. The name must be a
	 * String, but the value can be an arbitrary JsonElement, thereby allowing you
	 * to build a full tree of JsonElements rooted at this node.
	 *
	 * @param property
	 *            name of the member.
	 * @param value
	 *            the member object.
	 */
	public void add(String property, JsonElement value) {
		if (value == null) {
			value = JsonNull.INSTANCE;
		}
		members.put(property, value);
	}

	/**
	 * Removes the {@code property} from this {@link JsonObject}.
	 *
	 * @param property
	 *            name of the member that should be removed.
	 * @return the {@link JsonElement} object that is being removed.
	 * @since 1.3
	 */
	public JsonElement remove(String property) {
		return members.remove(property);
	}

	/**
	 * Convenience method to add a primitive member. The specified value is
	 * converted to a JsonPrimitive of String.
	 *
	 * @param property
	 *            name of the member.
	 * @param value
	 *            the string value associated with the member.
	 */
	public void addProperty(String property, String value) {
		add(property, createJsonElement(value));
	}

	/**
	 * Convenience method to add a primitive member. The specified value is
	 * converted to a JsonPrimitive of Number.
	 *
	 * @param property
	 *            name of the member.
	 * @param value
	 *            the number value associated with the member.
	 */
	public void addProperty(String property, Number value) {
		add(property, createJsonElement(value));
	}

	/**
	 * Convenience method to add a boolean member. The specified value is converted
	 * to a JsonPrimitive of Boolean.
	 *
	 * @param property
	 *            name of the member.
	 * @param value
	 *            the number value associated with the member.
	 */
	public void addProperty(String property, Boolean value) {
		add(property, createJsonElement(value));
	}

	/**
	 * Convenience method to add a char member. The specified value is converted to
	 * a JsonPrimitive of Character.
	 *
	 * @param property
	 *            name of the member.
	 * @param value
	 *            the number value associated with the member.
	 */
	public void addProperty(String property, Character value) {
		add(property, createJsonElement(value));
	}

	/**
	 * Creates the proper {@link JsonElement} object from the given {@code value}
	 * object.
	 *
	 * @param value
	 *            the object to generate the {@link JsonElement} for
	 * @return a {@link JsonPrimitive} if the {@code value} is not null, otherwise a
	 *         {@link JsonNull}
	 */
	private JsonElement createJsonElement(Object value) {
		return value == null ? JsonNull.INSTANCE : new JsonPrimitive(value);
	}

	/**
	 * Returns a set of members of this object. The set is ordered, and the order is
	 * in which the elements were added.
	 *
	 * @return a set of members of this object.
	 */
	public Set<Map.Entry<String, JsonElement>> entrySet() {
		return members.entrySet();
	}

	/**
	 * Convenience method to check if a member with the specified name is present in
	 * this object.
	 *
	 * @param memberName
	 *            name of the member that is being checked for presence.
	 * @return true if there is a member with the specified name, false otherwise.
	 */
	public boolean has(String memberName) {
		return members.containsKey(memberName);
	}

	/**
	 * Returns the member with the specified name.
	 *
	 * @param memberName
	 *            name of the member that is being requested.
	 * @return the member matching the name. Null if no such member exists.
	 */
	public JsonElement get(String memberName) {
		return members.get(memberName);
	}

	/**
	 * Convenience method to get the specified member as a JsonPrimitive element.
	 *
	 * @param memberName
	 *            name of the member being requested.
	 * @return the JsonPrimitive corresponding to the specified member.
	 */
	public JsonPrimitive getAsJsonPrimitive(String memberName) {
		return (JsonPrimitive) members.get(memberName);
	}

	/**
	 * Convenience method to get the specified member as a JsonArray.
	 *
	 * @param memberName
	 *            name of the member being requested.
	 * @return the JsonArray corresponding to the specified member.
	 */
	public JsonArray getAsJsonArray(String memberName) {
		return (JsonArray) members.get(memberName);
	}

	/**
	 * Convenience method to get the specified member as a JsonObject.
	 *
	 * @param memberName
	 *            name of the member being requested.
	 * @return the JsonObject corresponding to the specified member.
	 */
	public JsonObject getAsJsonObject(String memberName) {
		return (JsonObject) members.get(memberName);
	}

	@Override
	public boolean equals(Object o) {
		return (o == this) || (o instanceof JsonObject && ((JsonObject) o).members.equals(members));
	}

	@Override
	public int hashCode() {
		return members.hashCode();
	}
}
